Endoscope light source apparatus and endoscope system

ABSTRACT

An endoscope light source apparatus includes a turret provided with a first optical filter and a second optical filter for transmitting an illuminating light, an instruction section in which an operation instruction of the turret is inputted, a drive section that drives the turret, a first detector that detects a position of the turret, a first detected portion for identifying a position of the first optical filter, a second detected portion for identifying a position of the second optical filter, a second detector that optically detects a position of the first or the second detected portion, and a turret control section that outputs a drive signal to the drive section to move the turret until the first or the second detected portion is detected by the second detector and stop the turret in response to the first or the second detected portion being detected.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. Ser. No.13/652,796 filed on Oct. 16, 2012, which is a continuation applicationof PCT/JP2011/065983 filed on Jul. 13, 2011 and claims benefit ofJapanese Application No. 2010-159953 filed in Japan on Jul. 14, 2010,the entire contents of each of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope light source apparatus andan endoscope system, and more particularly to an endoscope light sourceapparatus that controls a turret provided with an optical filter fortransmitting an illuminating light, and an endoscope system that picksup an image of an object by the illuminating light that passes throughthe turret.

2. Description of the Related Art

When inspection/observation or treatment is performed with use of anendoscope, a light source apparatus that emits an illuminating light, avideo processor that processes an endoscopic image of an inspected sitepicked up by an image pickup device at an endoscope distal end, and amonitor that displays the processed endoscopic image are needed.

In a conventional light source apparatus for an endoscope, a pluralityof filters are prepared and selection is made from the filters for useto adjust a light amount, a color tone and the like to a proper lightamount, a proper color tone and the like in accordance with a kind of abody cavity to be observed, exposure at a time of photographing, a lightamount of a light source lamp and the like. Further, an emergency lightwhich is used in place of the light source lamp when the light sourcelamp fails during use of the light source lamp is also prepared.

The various filters and the emergency light are disposed at acircumferential portion of a turret, which is rotatably provided, alonga circumferential direction thereof. The above-described turret isrotated, whereby the various filters and the emergency light which areneeded are located on an emission light path (refer to, for example,Japanese Patent Application Laid-Open Publication No. 2001-343595).

The conventional turret includes a motor for rotating the turret, and apotentiometer mounted to a rotary shaft to detect a rotational angle ofthe turret.

In order to locate the filter corresponding to a use purpose on theemission light path out of a plurality of filters on the turret, it isnecessary to correctly match a center of the target filter with anoptical axis of the emission light by rotating the turret by a requiredangle.

SUMMARY OF THE INVENTION

An endoscope light source apparatus of one aspect of the presentinvention includes a turret provided with a first optical filter and asecond optical filter for transmitting an illuminating light, aninstruction section in which an operation instruction of the turret isinputted, a drive section that drives the turret, a first detector thatdetects a position of the turret, a first detected portion foridentifying a position of the first optical filter, a second detectedportion for identifying a position of the second optical filter, asecond detector that optically detects a position of the first or thesecond detected portion, and a turret control section that outputs adrive signal to the drive section to move the turret until the first orthe second detected portion is detected by the second detector in orderto position the optical filter designated in response to an input of theinstruction section, after moving the turret to an inside of a firstrange detected by the first detector, in response to the input of theinstruction section, and stop the turret in response to the first or thesecond detected portion being detected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an endoscope system according to thepresent invention;

FIG. 2 is a plan view showing a structure of an endoscope light sourceapparatus interior of a first embodiment of the present invention;

FIG. 3A is a perspective view showing a structure of a turret at anincident side;

FIG. 3B is a perspective view showing a structure of the turret at anexit side;

FIG. 4 is a perspective view showing a position adjustment structurethat is used at a time of assembly of diaphragm blades;

FIG. 5 is an electric control block diagram of a light source apparatus;

FIG. 6 is a flowchart of a control operation;

FIG. 7 is a flowchart of a control operation;

FIG. 8 is a block diagram showing an endoscope system of a secondembodiment of the present invention; and

FIG. 9 is a diagram showing a relation of a CCD signal output, a turretrotational angle and a potentiometer voltage.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings.

FIG. 1 is a block diagram showing an endoscope system according to thepresent invention.

In FIG. 1, an endoscope system 10 includes an endoscope 20 that includesa light guide 21 that guides an illuminating light to a distal endportion and a CCD 22 as an image pickup device that performs imagepickup of a subject, a light source apparatus 30 that emits light to thelight guide that supplies the illuminating light to an endoscope distalend portion, a video processor 50 that processes an endoscope image ofan inspected site that is picked up by the CCD 22 at the endoscopedistal end portion, and a monitor 60 that displays the processedendoscopic image.

First Embodiment

FIG. 2 is a plan view showing a structure of an endoscope light sourceapparatus interior of a first embodiment of the present invention. FIG.2 corresponds to an interior structure of the light source apparatus 30in FIG. 1.

In FIG. 2, the light source apparatus 30 includes a power supply section31 that supplies electric power to respective sections in the lightsource apparatus 30, a lamp section 32 that supplies an illuminatinglight to the light guide of the endoscope 20, a control board 33 thatincludes an input/output terminal 33 a that outputs a motor drive signalto a turret 34, and receives a potentiometer detection signal from theturret 34, and includes instruction means that gives an operationinstruction to the turret 34 and turret control means that controls theturret 34, the turret 34 that includes an optical filter (hereinafter,sometimes simply called a filter) that transmits a light from a lampfrom the lamp section 32, a motor 35 as drive means that rotationallydrives the turret 34, a potentiometer 36 as a first detector thatdetects the rotation angle as a position of the turret 34, a lens 37 forconverging an emission light, a diaphragm 38 for adjusting a lightamount of the emission light, a scope insertion port 39 to which thelight guide which is light guide means of an insertion portion of theendoscope (scope) is connected, and a photo reflector 40 as a seconddetector that detects a position in a range narrower than a range thatis detected with the potentiometer 36 that is the first detector. Notethat the lamp section 32 is shown in a state in which the lamp section32 is placed by being overlaid on the power supply section 31.

FIG. 3A and FIG. 3B are perspective views showing a structure of theturret 34, FIG. 3A shows a perspective view of the turret 34 seen froman incident side, and FIG. 3B shows a perspective view of the turret 34seen from an exit side respectively.

On the incident side of the turret 34, cylindrical frame bodies providedwith optical filters 341 and 342 respectively are mounted to an incidentside plane of a filter disk 340 with screws as shown in FIG. 3A.Further, a back surface side of an emergency light 345 is mounted to theincident side plane of the filter disk 340 with screws by using amounting frame. Further, to the incident side plane of the filter disk340, optical path shielding plates 343 and 344 are fastened with screwsin such a manner as to close circular optical filter mounting holeportions (holes for use in the case of new optical filters being added)from the incident side, with respect to the circular optical filtermounting hole portions.

Note that if the optical filter is not installed on the turret 34, theportion corresponding thereto needs to be shielded with an optical pathshielding plate as a mask. If the two optical path shielding plates 344and 343 are not present in FIG. 3A, three regions where optical filterscan be placed are vacant, and the mass balance on the filter disk 340 islost, as a result of which, excessive load is exerted on the turretrotating motor 35, but if suitable masses are given to the optical pathshielding plates 344 and 343, the mass balance can be substantiallyrestored by the optical path shielding plates 344 and 343 being placedin the two optical filter vacant regions of the filter disk 340.Furthermore, when the optical path shielding plates 344 and 343 areremoved from the state of FIG. 3A, and two of new optical filters aremounted on the two vacant optical filter regions, one of the opticalpath shielding plates 344 and 343 that is suitable from the viewpoint ofmass out of the optical path shielding plates 344 and 343 which areremoved in advance is placed on the vacant region (region where the holeis not provided) at an upper right side of FIG. 3A, whereby the massbalance can be kept more properly.

On the exit side of the turret 34, fitting portions of the opticalfilters 341 and 342 are mounted to an emission side plane of the filterdisk 340 to be projected to some degree as shown in FIG. 3B. Further, alight emission side of the emergency light 345 is mounted to theemission side plane of the filter disk 340 to be projected with thehighest height. Furthermore, it is shown that on the emission side planeof the filter disk 340, the above-described optical path shieldingplates 343 and 344 block the circular optical filter mounting holeportions. In addition, on the emission side plane of the filter disk340, six columnar detection bodies 346 the number of which is the sameas the number of a plurality of (six in the drawing) optical filterregions which can be placed in a circumferential direction of an outeredge of the turret 34 are projectingly provided. The plurality ofcolumnar detection bodies 346 are formed so that all heights thereof arethe same heights, and the heights of the respective detection bodies 346are formed to be such heights that exceed the maximum value of theheights of the plurality of projected portions which appear on theemission side of the turret 34. It is necessary that the plurality ofcolumnar detection bodies 346 receive light from the photo reflector 40(refer to FIG. 5) which will be described later, reflect the light ondetection bodies distal end surfaces thereof, and thereby enabling thephoto reflector 40 to receive the reflected light thereof and reliablyperform positional detection. Accordingly, in the filter plane 340 ofthe turret 34, regions other than the distal end surfaces of theplurality of columnar detection bodies 346 are preferably coated with anirreflexive member (for example, a black color coating material) whichdoes not reflect the light from the photo reflector 40.

As above, the reference position of the turret is configured by thecolumnar detection body for each of the respective filters, andtherefore, the structure can be realized, in which even if a pluralityof projected portions which are projected are present on the surface ofthe turret, the reference positions can be reliably read with the seconddetector at low cost.

FIG. 4 shows a structure which applies a measure to be able to realizeenhancement of assembly precision and enhancement of assemblyoperability, in an assembly process of a diaphragm blade 38 a as lightamount control means which is placed on the light emission side of theturret 34 in the light source apparatus 30. FIG. 4 shows a configurationin which in a support body 70 that rotatably supports the diaphragmblade 38 a, slits 71 and 72 are provided on a top and a bottom of amounting portion (recessed place portion) of the diaphragm blade 38 awhich is formed in the support body 70, and positional adjustment of thediaphragm blade 38 a is performed in correspondence with the slits 71and 72 on the top and the bottom. The slits are provided on the top andthe bottom of the mounting frame of the diaphragm blade 38 a, whereby itbecomes possible to determine that the positional adjustment of thediaphragm blade 38 a is favorable when the slits 71 and 72 on the topand the bottom and the diaphragm blade 38 a are aligned in one straightline when the slits 71 and 72 and the diaphragm blade 38 a are seen fromdirectly above. Thereby, enhancement of the assembly precision and theassembly operability of the diaphragm blade can be realized.

FIG. 5 shows an electric control block diagram of the light sourceapparatus 30. The same sections as the sections in FIG. 2 are assignedwith the same reference signs.

In FIG. 5, the light source apparatus 30 includes the power supplysection 31, the lamp section 32, the control board 33, the turret 34,the motor 35, the potentiometer 36, the detection bodies 346 and thephoto reflector 40.

The potentiometer 36 is mounted to a rotary shaft of the turret 34, andan output signal thereof is sent to the control board 33. The photoreflector 40 detects the detection body 346 which is disposed at each ofthe optical filters, and an output signal thereof is sent to the controlboard 33.

An angle of the turret 34 at which the photo reflector 40 detects thedetection body 346, and an angle of the turret 34 at which the opticalfilter enters the optical path are the same.

The detection body 346 which the photo reflector 40 detects is placed ateach of the optical filters, which enters the optical path. Therefore,it is determined that for each of the optical filters, in the case ofwhich angle, detection of the detection body 346 is performed, and theturret angles at which the six detection bodies 346 (refer to FIG. 3B)are present, that is, the angles at which the six optical filters enterthe optical path increase by 60° from an angle at the time of start ofrotation.

The control board 33 includes a FPGA (abbreviation of field programmablegate array) 331 including a lamp current regulating section 3311 and aturret control section 3312, a CPU 332 including an instruction section332 a as instruction means that gives an operation instruction to theturret 34, a lamp control circuit 333 including a lamp overvoltagedetecting circuit 333 a, a motor driver 334 of the motor 35, an A/Dconverting section 335 that A/D-converts a detection signal of thepotentiometer 36, and a level converting section 336 that converts alevel of a detection signal of the photo reflector 40.

The lamp current regulating section 3311 provided in the FPGA 331switches an observation light mode and at the same time, switches a lampcurrent in the lamp current regulating section 3311 when endoscopeobservation is performed with an observation light of a differentwavelength, whereby observation of a bright image is always enabled. Forexample, when a normal light observation mode by a white light (WL) anda special light observation mode by a narrow band light (NBI) areavailable, brightness on the monitor is very low at the time of NBIobservation as compared with the WL observation. In contrast with this,the brightness on the monitor is conventionally gained by an electricgain (AGC) being increased, but noise also increases, and therefore, S/Nbecomes worse at the time of NBI observation. Therefore, at the time ofNBI, input power (voltage, current) to the lamp is increased more thanat the time of WL, whereby the brightness of the image on the monitorcan be increased without noise being increased.

The turret control section 3312 provided in the FPGA 331 outputs a drivesignal to the motor 35 that is drive means so as to move the turret 34to an inside of a second range which is narrower than an inside of afirst range and is detected by the photo reflector 40 that is a seconddetector after moving the turret 34 to the inside of the first rangedetected by the potentiometer 36, based on the outputs from theaforementioned instruction section 332 a as the instruction means, andthe potentiometer 36 that is a first detector.

As above, a drive signal of the motor 35 is controlled with the turretcontrol signal from the turret control section 3312. A rough angle ofthe turret 34 is detected with the potentiometer that is the firstdetector, and detailed position detection of the turret 34 can beperformed with the second detector, and improvement of the turret stopposition precision can be realized.

The lamp control circuit 333 includes the lamp overvoltage detectingcircuit 333 a. The lamp overvoltage detecting circuit 333 a is a circuitfor turning off the lamp when a lamp of the lamp section 32 fails and isbrought into a state in which an overvoltage occurs to the lamp, andturns off the lamp when the voltage exceeds a threshold value byproviding the threshold value at the lamp voltage. Thereby, a patientcan be prevented from getting scalded by the lamp failing to cause anexcessive current of a rated current or more to flow and the lamp havingan excessive light amount.

FIG. 6 and FIG. 7 are flowcharts of a control operation. Note that FIG.6 and FIG. 7 are of one flowchart, but expressed as two diagrams becauseof the paper space.

A control method will be described with reference to FIG. 6 and FIG. 7.

In step S1, in the control board 33, when hardware receives a drivecommand of the turret 34 regarding a target position from software, theoutput voltage of the potentiometer 36 at the present position isdetected.

In step S2, an output voltage range of the potentiometer 36 for allowingthe optical filter at the target position to enter the optical path heldby the hardware in advance is called.

In step S3, the results of steps S1 and S2 are obtained, the outputvoltage of the potentiometer 36 at the present position and the outputvoltage range for causing the optical filter of the target position toenter the optical path are compared with each other, and a drivedirection of the motor 35 is determined

a. Potentiometer voltage at the present position>potentiometer voltagerange of the target positioner

rotates in the direction which lowers the voltage value of thepotentiometer

b. Potentiometer voltage at the present position<potentiometer voltagerange of the target positioner

rotates in the direction which raises the voltage value of thepotentiometer

In step S4, the motor 35 is driven, and the turret 34 is rotated.

In step S5, it is determined whether or not the photo reflector 40 whichis the second detector always outputs the signal indicating that thephoto reflector 40 detects the detection body 346. Further, in step S5′,it is determined whether or not the photo reflector 40 always outputsthe signal indicating that the photo reflector 40 detects non-detectionsection (region coated with the irreflexive member).

When in any one of steps S5 and S5′, the signal detecting the detectionbody or non-detection section is always outputted, it is determined thatan error occurs (step S5″), and drive of the turret 34 is stopped (stepS5′″).

In step S6, it is found out whether the current potentiometer outputvoltage is in the target potentiometer output voltage range.

When the current potentiometer output voltage is within the targetvoltage range, the flow proceeds to step S7.

When the current potentiometer output voltage is outside the targetvoltage range, the flow proceeds to step S6′, and from the comparisonresult in step S3, it is determined whether the turret 34 is rotated asit is, or rotated in the opposite direction.

When the comparison result in step S3 is a, the turret 34 is rotated ina direction which lowers the potentiometer voltage, but when“potentiometer voltage at the present position<the potentiometer voltagerange of the target position” is satisfied, the turret 34 is excessivelyrotated, and therefore, the turret 34 is rotated in the oppositedirection as shown in step S6.″ Otherwise, the turret 34 is rotated asit is.

When the comparison result in step S3 is b, the turret 34 is rotated ina direction which raises the potentiometer voltage, but when“potentiometer voltage at the present position>potentiometer voltagerange of the target position” is satisfied, the turret is excessivelyrotated, and therefore, the turret is rotated in the opposite directionas shown in step S6.″ Otherwise, the turret is rotated as it is.

In step S7, in order to find out that the photo reflector 40 detects thedetection body 346, a rising edge of a photo reflector output signal ata time of the detection body 346 being detected is detected.

When the rising edge is detected, the flow proceeds to step S8.

When the rising edge is not detected, the flow proceeds to step S7′, andfrom the comparison result in step S3, it is determined whether theturret 34 is rotated as it is, or rotated in the opposite direction.

When the comparison result in step S3 is a, the turret 34 is rotated inthe direction which lowers the potentiometer voltage, but when“potentiometer voltage at the present position<potentiometer voltagerange of the target position” is satisfied, the detection body 346 isnot detected, and therefore, the turret 34 is rotated in the oppositedirection as shown in step S7,″ whereby detection of the detection body346 is performed. Otherwise, the turret 34 is rotated as it is, anddetection of the detection body 346 is continued.

When the comparison result in step S3 is b, the turret 34 is rotated inthe direction which raises the potentiometer voltage, but when“potentiometer voltage at the present position>potentiometer voltagerange of the target position” is satisfied, the detection body 346 isnot detected, and therefore, the turret is rotated in the oppositedirection as shown in step S7,″ whereby detection of the detection body346 is performed. Otherwise, the turret 34 is rotated as it is, anddetection of the detection body 346 is continued.

In step S8, the output voltage value of the potentiometer 34 at the timeof the rising edge of the photo reflector output signal being detectedis retained. The retained value is set as (A).

In step S9, a control signal that stops the motor 35 is sent.

In step S10, even after the control signal that stops the motor 5 issent, the turret 34 also rotates as the motor 5 rotates by inertia, andtherefore, in order to find out that rotation of the turret 34completely stops, it is found out that there is no variation of theoutput voltage value of the potentiometer 36.

In step S11, there is the possibility that the photo reflector 40 doesnot detect the detection body 346 due to the influence of the rotationby the inertia of the motor 34 of step S10 when the rotation of theturret 34 stops, and therefore, it is ascertained that the photoreflector 40 detects the detection body 346.

When the photo reflector 40 detects the detection body 346, the flowproceeds to step S12.

When the photo reflector 40 does not detect the detection body 346, theflow proceeds to step S13, the potentiometer output voltage at the timeis retained, and a value thereof is set as (B).

The potentiometer output voltage (A) retained in step S8 and the currentpotentiometer output voltage (B) are compared, and if the currentpotentiometer output voltage overruns, the rotational direction of theturret is determined to be the direction to approach the potentiometeroutput voltage value (A) (step S14). The turret 34 is rotationallydriven in step S15.

In step S12, the drive of the turret 34 is completed, and therefore, thesoftware is notified of the completion of the movement, and the drive ofthe turret 34 is completed.

Note that the second detector may be an optical sensor such as a photointerrupter, besides the photo reflector 40. In the case of the photointerrupter, drive of the motor 35 can be stopped when a matter whichblocks the optical path between the LED and the sensor enters.

The detection body 346 may be either a reflective body or an irreflexivebody, and the user can make choice.

When the photo reflector 40 is used, a sheet metal portion with a highreflectivity and a silk portion with a low reflectivity are inverted andan area of the silk portion is made large, so that the LED lightemission of the photo reflector does not become disturbance noise toother photo reflectors, whereby the influence of the disturbance noiseis suppressed.

According to the first embodiment, when control of the rotation angle ofthe turret is performed, the rough angle is detected with thepotentiometer that is the first detector, and the detailed positionaldetection can be performed with the second detector. The detailedpositional detection of the rotation angle is performed at the positionapart from a center, whereby detection with higher precision than asubstantially center of the turret can be performed even when thedetection precision is equivalent. Furthermore, when the rotationcontrol of the turret is to be performed with only the second detector,the second detectors the number of which corresponds to the number ofthe detection positions are required in the outer circumferentialdirection of the turret, the cost increases and the size also increases,whereas in the present first embodiment, by combination with the firstdetector, improvement of the turret stop position precision is realized,and the stop precision of the turret can be enhanced at low cost with arelatively simple system.

Second Embodiment

FIG. 8 is a diagram showing an endoscope system of a second embodimentof the present invention.

In FIG. 8, an endoscope system 10A includes the endoscope 20 includingthe light guide 21 as light guide means that guides an illuminatinglight to the distal end portion and the CCD 22 as the image pickupdevice that picks up an image of a reflected light image from an object80, the light source apparatus 30 that emits light to the light guide 21that guides the illuminating light to the endoscope distal end portion,the video processor 50 which performs signal processing of an endoscopicimage picked up with the CCD 22 at the endoscope distal end portion, themonitor 60 that displays the endoscopic image which is subjected tosignal processing, and a power supply section (not illustrated). In thesecond embodiment of FIG. 8, the second detector shown in the firstembodiment is not required.

The light source apparatus 30 includes the FPGA 331 and the CPU 332, thelamp section 32, the turret 34 including the optical filter 341, themotor 35 as the drive means including a gear 351, the potentiometer 36as the detector that detects the position of the turret 34, the motordriver 334 that drives the motor 35, the A/D convertor 335 thatA/D-converts the output of the potentiometer 36, a memory 337 as storagemeans that stores information for driving the turret 34, and the scopeinsertion port 39.

The above described FPGA 331 and CPU 332 include an instruction section332 b as instruction means that performs instruction to cause the memory337 to store information for driving the turret 34, and a turret controlsection 331 a as turret control means that outputs a drive signal forcausing the turret 34 to make one rotation to the motor 35 and stores adetection value from the potentiometer 36 at which a measured value froma photometry section 43 a as photometry means becomes a maximum valuewhile the turret 34 makes one rotation, into the memory 337 by theinstruction of the instruction section 33 b.

The video processor 50 includes a preamplifier 41, an A/D convertor 42,and an FPGA 43 including the photometry section 43 a as the photometrymeans that generates a photometric signal from the image pickup signalfrom the CCD 22 and outputs the photometric signal. The photometrysection 43 a in the FPGA 43 calculates a level of brightness (lightoutput intensity) received by the CCD 22, and outputs the level of thebrightness to the FPGA 331 and the CPU 332 in the light source apparatus30.

In the above-described configuration, an output voltage of thepotentiometer 36 and the level of the brightness received by the CCD 22are associated with each other, and a potentiometer voltage at which abrightness peak is present is used as a positioning target value(reference) of the turret 34.

For association, adjustment steps 1 to 6 as follows are required.

1: The light source apparatus 30, the video processor 50, and a whitechart as the object 80 are prepared, and the lamp is lit.

2: The turret 34 is rotated at a desired rotational speed from a certainposition until all the filters pass through the optical axis (rotationis optional, such as one rotation, a plurality of rotations, and areverse rotation).

3: The output voltage of the potentiometer 36 at the time of the stateof 2 is read, and is taken into the FPGA 331/CPU 332.

3: CCD output which is the result of receiving a reflected light fromthe white chart at the time of the state of 2 is taken into the FPGA331/CPU 332 of the light source apparatus 30 as brightness informationvia the video processor 50.

4: The relation of the potentiometer output voltage and the brightnessinformation can be calculated from 3 and 3′.

5: If six optical filters are present, the output of the CCD 22 has sixbrightness peaks, and therefore, the output voltages at the time ofoutput thereof are referred to and stored in the memory 332.

6: The stored voltages are used as a stop angle reference of the turret34, and drive control of the turret 34 is performed with the controlmethod similar to the conventional control method.

Note that the present adjustment steps can be performed duringinspection (aging of the lamp and the turret) of the light sourceapparatus 30, for example, and therefore, the number of adjustmentprocess steps is not required additionally.

Having the brightness peak means that the filter of the turret comes tothe optical axis, and therefore, becomes the reference for positionalcontrol.

In place of the CCD, an optical sensor, a power meter or the like may beused.

The peak detection method may be a method which causes the turret tomake a plurality of rotations and takes an average value of the numberof plurality of rotations and the like, besides the method for takingthe peak when the turret makes one rotation.

FIG. 9 is a diagram showing a relation of the CCD signal output, theturret rotation angle and the potentiometer voltage. Before shipment orbefore use of the light source apparatuses, the potentiometer voltagescorresponding to the CCD output peaks (turret rotation angles) aremeasured and stored in advance in the memory 337 individually for theactual light source apparatuses.

According to the second embodiment, the stop precision of the turret canbe enhanced without adoption of a potentiometer with high precision orincrease of mechanical precision, and without increase of cost with thelight source apparatus and the configuration of the turret in theconventional art being kept.

The present invention is not limited to the embodiments described above,and various modifications, alterations and the like can be made withinthe range without departing from the gist of the present invention.

What is claimed is:
 1. An endoscope system that controls a turretprovided with an optical filter for transmitting an illuminating light,and picks up an image of an object by the transmitted illuminatinglight, comprising: light guide means for guiding the illuminating light;an image pickup device that picks up an image of an object illuminatedwith the illuminating light guided by the light guide means; photometrymeans that generates a photometric signal from an image pickup signalfrom the image pickup device and outputs the photometric signal; aturret provided with an optical filter for transmitting the illuminatinglight; a detector that detects a position of the turret; drive meansthat drives the turret; storage means that stores information fordriving the turret; instruction means that performs instruction forcausing the storage means to store information for driving the turret;and turret control means that outputs a drive signal for causing theturret to make one rotation to the drive means, and stores a detectionvalue from the detector at which a photometric value from the photometrymeans becomes a maximum value while the turret makes the one rotation,into the storage means, by the instruction of the instruction means.